Field of the Invention
The present invention relates to a sheet conveying apparatus and an image forming apparatus.
Description of the Related Art
Some image forming apparatuses, such as copiers and printers, are capable of printing on both sides of a sheet. As shown in FIG. 9, Japanese Patent Laid-Open No. 2006-62808 discloses a typical configuration for double-sided printing in which a double-sided conveying unit 102 is disposed above a cassette 100 detachable from the main body 103 of an image forming apparatus.
In the configuration disclosed in Japanese Patent Laid-Open No. 2006-62808, a sheet is conveyed from the cassette 100 set at the lower part of the apparatus main body 103 to an image forming unit 101 to form an image on the first surface of the sheet. The sheet is then reversed and conveyed to the double-sided conveying unit 102, with which the sheet is conveyed again to the image forming unit 101, in which an image is formed on the second surface, and the sheet is discharged out of the apparatus main body 103.
The double-sided conveying unit 102 is releasable so as to clear a jam therein. A configuration for clearing the jam will be described with reference to FIGS. 10A to 10C.
FIG. 10A is a perspective view of the configuration, and FIGS. 10B and 10C are cross-sectional views thereof. As shown in FIGS. 10A to 10C, the double-sided conveying unit 102 includes a sheet conveying unit 107 and a double-sided conveyance guide 102a that guides a sheet conveyed by the sheet conveying unit 107. The sheet conveying unit 107 and the double-sided conveyance guide 102a are disposed in the apparatus main body 103. A sheet cassette 100 is detachably attached below the double-sided conveying unit 102.
As shown in FIGS. 10A to 10C, a shaft (not shown) secured to the apparatus main body 103 is supported in a hole 104 so that the double-sided conveying unit 102 is rotatably mounted to the apparatus main body 103. A downstream side of the double-sided conveying unit 102 in the sheet conveying direction (hereinafter referred to as “downstream side”) is fixed to the apparatus main body 103 in such a manner that an upstream side in the sheet conveying direction (hereinafter referred to as “upstream side”) is released. If sheet clogging (hereinafter referred to as “jam”) occurs in the double-sided conveying unit 102, the user first draws the cassette 100, as shown in FIG. 10B. Then the user pushes down a lever 106 disposed at the double-sided conveying unit 102 adjacent to the front of the apparatus main body 103 to release the double-sided conveying unit 102. This allows the user to access the interior of the double-sided conveying unit 102 to clear the jam.
FIGS. 11A and 11B illustrate a known configuration including the rotatable lever 106 to release the double-sided conveying unit 102.
However, size reduction of the apparatus can lead to interference between the path of the rotation of the lever 106 and the path of the movement of the cassette 100 during inserting and extracting operations. The operation of inserting and extracting the cassette 100 can cause the lever 106 to malfunction, or the lever 106 can interfere with the operation of inserting and extracting the cassette 100.
The present invention provides a compact sheet conveying apparatus and a compact image forming apparatus in which the operation of inserting and extracting a cassette (a stack unit) is not interfered with.